Gun perforator and firing device therefor



J. JOHNSON Nov. 23, 1943.

GUN PERFORATOR AND FIRING DEVICE THEREFOR 2 Sheets-Sheet 1 Filed March17, 1941 i 5 y mm 4 5 M 9. E x ,P ,a .u M U y n# 5 JJ g3g@ M n @Ming y,o Q n 8 1.2: A0//7/ u.. Lmm l i il j il 2Q y ,w :f m a?, y ZZ g2g ngi Mggg@ ATTORNE Nov. 23, 1943. .1 JOHNSQN 2,334,931

' GUN PERFORATOR AND FIRING DEVICE 'pHEnEFoR Filed Marcy 17,' 1941 '2sheets-sheet 2 ATTORNE Patented Nov. 23, 1943 GUN PERFORATOR AND FIRINGDEVICE THEREFOR Jack Johnson,

Compton,

Calif., assig-nor to Methox Well Cleaning Corp., Long Beach, i Calif., acorporation of California Application March 17, 1941, Serial No. 383,727

20 Claims.

My invention relates to explosive operated tools for use 'in oil wellsand also to a firing mechanism therefor and has particular` reference toan explosive operated casing perforator and a firing device forcontrolling the operation of the same.

Certain of the tools used in the oil producing industry in connectionwith the drilling of deep wells and the production of oil and gastherefrom are arranged to be operated by the energy developed throughthe firing of an explosive charge. Such tools include gun perforatorsfor perforating casing in the event it is desired to produce oil and gasfrom a previously sealed off productive zone, torpedoes such as are usedfor cleaning screens and for the jarring of the formation for thepurpose of expediting the flow of oil and gas therefrom, and certainpacker setting devices such as are used for the setting of packers inconnection with oil well cementing operations and the setting of owtubing. Most of these tools are equipped with firing devices, and twowell known types of firing devices are in general commercial use. Onesuch type of firing device is connected to certain control mechanism atthe ground surface by means of one or more electric'al conductors builtinto the supporting cable which is used to lower the tool into the wellbore.

This type of` cable is very expensive anddue to the reeling andunreeling of the cable and the passing of the cable over relativelyshort radius blocks vand pulleys, is subject to the breaking of one ormore of the electrical conductors. The breaking of the conductorsrenders the ring device inoperative and necessitates the expenditure ofconsiderable time and money in determining the location of the break andin the sub` sequent repairing of the break. Furthermore, this type ofcableis extremely heavy so that special equipment must be employed forits handling, and cables of this type require special and carefulhandling in order to avoid injury to the electrical conductors includedtherein.

The other commonly employed type of ring device comprises a triggermechanism so arranged that a weight or go-devil surrounding the cableused Lto lower the tool into the oil well may be dropped from the groundsurface after the tool and the go-devil may be arrested in its fallbefore it reaches the device due to the bearing of the supporting cableagainst the sides of the well bore. Furthermore, the travel of thego-devil down the supportingcable subjects the cable to undue wear andabrasion, with the occasional result that the cable will break while thetool is lowered into the well bore, with the result that thetool and aportion of the cable are lost in the bore, necessitating an expensivefishing operation in order to retrieve the lost equipment.

It is, therefore, an object of my invention to provide a firing devicefor explosive operated oil well tools which overcomes the above noteddisadvantages by including a means operable from the ground surface toactuate the explosive operated tool without the use of lgo-devils orelectrcal conductors extending tothe ground surface.

It is also an object of my invention to pro-4 vide a firing device ofthe character set forth in the preceding paragraph in which an inertiadevice, responsive to abrupt vertical movement,

is employed forigniting an explosive charge.

`It is an additional object of my invention to provide a firing deviceof the character set forth in the preceding paragraphs in which a timingY means is employed for rendering the inertia device inoperative untilafter the elapse of a predetermined time.

. It is a still further object of my invention to' provide a iiringdevice of the character set forth has been positioned as desired in thewell, the

,cable serving to guide the go-devil in its fall through the well boreand the impact of the go devil with the trigger' serving to actuate the`firing mechanism.

This type of firing device is unsatisfactory for the reason that the'well bores are never straight hereinbefore in which an electricallyoperated igniter is connected in series with an inertia switchactuatable to complete a firing circuit by an abrupt vertical movementof the device and in which a timing means is employed for maintainingthe firing circuit open irrespective of actuation of said inertia switchuntil after the elapse of a predetermined time.

It is additionally an object of my invention to provide a ring device ofthe character set forth in the foregoing in which a second timing meansis employed for also preventing actuation of said inertia switch untilafter the elapse of a predetermined time.

It is a still further object of my invention to provide a firing deviceof the character set forth in the preceding paragraphs which includes atiming mechanism for preventing actuation of the tiring device if 'thedevice is not actuated within apredetermined time period.

Among the various explosive operated oil well tools above referred to isincluded the class of tors.' During the drilling of an oil well itfrequently happens that a potential oil producing zoneis passed up andsealed oir for the purpose of extending the well bore into a deep oilbearing stratum. Subsequent conditions, such as the exhausting ofthelower strata, make it desirable to start production from thepreviously sealed off strata. Casing perforators are employed forpunching a number of holes through the casing at the location of thesealed oi zone, and for this purpose gun or explosive operatedperforators have been found to be particularly advantageous. G unperforators of the character at present employed do, however, includethe disadvantage o1 the lack of adjustability as regards the diameter ofcasing which they are adapted toperforate;

cludes a plurality of removable gun barrel units whereby units ofvarious lengths may be installed,

depending upon the diameter of the casing to be perforated.

It is also an object of my invention to provide a gun perforator of thecharacter set forth in the preceding paragraph in'which a novelconstruction is employed -for resisting the expulsion of the bulletuntil considerable pressure is built up in the ring chamber and for alsopreventing the ingress of water and the like to the explosive material.

Other objects and advantages of my invention will be apparent from astudy oi the following specifications, read in connection with` theaccompanying drawings; wherein:

Fig. 1 is an elevational view illustrating the firing device of myinvention as being arranged to actuate a gun perforator, the ring deviceand gun/perforator being illustrated as having been lowered to a desiredposition in a well bore;

Fig. 2 is a longitudinal section illustrating the details ofconstruction of .the ring devic'e shown l in Fig. 1;

Fig. 3 isa perspective view illustrating the appearance and constructionof a part of a timing means employed in the ring device shown in Fig. 2;

Fig. 4 is a, fragmentary sectional View illustrating the manner in whichan electrical connection is obtained to the case or negative terminal ofa battery used in the iring device;

Fig. 5 is a longitudinal section illustrating the details ofconstruction of the gun perforator Fig. 6 is a perspective viewillustrating the construction and appearance of a removable gun barrelunit incorporated in the perforator of Fig. 5; Fig. 'I is an enlargedsectional view illustrating the manner in which a longer gun barrel unitmay be substituted for the purpose of adapting the perforator for usewith large diameter casings; and A Flg. 8 is a fragmentary sectionalview similar to Fig. 7 but illustrating a modined form of my inventionemploying a unitaryl cartridge and projectile assembly adapted tosimultaneouslyv perforate opposite sides of a well casing.

Referring to the drawings, I have illustrated' in Fig. 1 a section of awell bore I as being lined potentially productive zone 3.

The firing 'device is illustrated in detail in Fig. 2 as comprising anouter tubular housing or shell I tted at its upper end with a suitableadapter or cable socket II for attaching the supporting cable 1 thereto.The lower end of the housing I0 is preferably provided with male threadsI2 adapted to be received within corresponding female threads I3 formedon the uppery end of a collar or connector I4, which connector isprovided at its lower end with a pin I permitting threaded attachment ofthe ring device 5 to the perforator 6 or other explosive operated oilwell tool.

The connection afforded by the threads I2 and vI3 provides for theremoval of the adapter I4 which in turn permits the insertion into orremoval from the housing I0 of a support I6. The support I6 ispreferably formed from a section of tubing having an outside diameterYadjusted to be closely received Within the inside of the housing I0, thetube being cut away as indicated at I 1 and I8 to permit ready access tovarious instrumentalities carried by the support I6 when the, support isremoved from the housing I0. When installed within the housing I 0, thesupport I6 is urged downwardly as by means of a compression spring 'I 9into engagement with a shoul der formed on the interior of the connectorI4.

Upon the support I6 I mount an inertia responsive mechanism 2| adaptedto be actuated in response to a sudden vertical movement of the housingIIJ and close an electrical switch 22, the closing of which iscontrolled by means of an interlocking lever 23. The electrical switch22 is included in a series circuit comprising the switch 22, one or moredry'cells or batteries 24, and an igniter 25 so that closing of theswitch 22 will energize the igniter 25 and explode a small quantityofexplosive 26 disposed in contact with the igniter.

The igniter 25 may conveniently comprise a spark plug 0f substantiallystandard construction, between the electrodes of which is connected apiece of small wire 21 adapted to be lheated to incandescence when theaforementioned electrical circuit is closed. 'Ihe igniter 25 ispreferably secured into a bore 28 formed in the connector I4 as by meansof screw threads 29 and the bore 28 preferably extends completelythrough v'the connector I4 in an axial direction. The bore 28 ispreferably constricted as indicated at 30 to provide a seat for a ballcheck valve 3l normally urged against the seat by means of a compressionspring 32 which is conned between the ball 3| and a bushing 33 threadedinto the lower end of the bore 28.

'I'he explosive charge 26 is conned between the checkvalve 3| and theigniter 25. Thus, when the charge 26 is flred by energization of theigniter 25, burning gases, the products of the combustion o1' theexplosive 26, are projected past the valve 3| and downwardly through thebore 28 so as to set nre. ignite or explode the explosive materialcarried by the explosive operated tool a value substantially equal tothe 4support I6 as by means extending arm portion or case of the dry 6to which the ming device 5 is attached. Whenever the pressure developedby therexplosion of the explosive contained within the tool 6 rises topressure developed by the ignition of the charge 26, the check valve 3|will close and so prevent the full force and effect of the resultingexplosion from being impressed upon the igniter 25. This serves to avoidthe risk of the igniter being loosened or dislodged from its attachmentto Vthe connector I4.

\ The inertia actuated device 2|` above referred to preferably includesa laterally extending supporting member 34 which may be secured to theof screws which rises an upwardly extending tubular stem 36. The tubularstem V36 31 which is secured at its upper end to a weight or cap 38which is in turn provided with a cylindrical recess 39 adapted toreceive the upstanding end of the tubular guide pin 31 are thus slidablysupported by the stem 36 for vertical movement relative to the housingpreferablyA lli. The weight of these members is normally supported .bymeans of a compression spring 40 interposed between the laterallyextending support 34 and the lower end of the weight-38. The weight 38will, therefore, normally remain stationary relative to the housing Ibut will be responsive to acceleration or deceleration of the housing,at whichy time the weight 36 will be urged either upwardly ordownwardly.

Undesired upward movement of the weight 38 is preferably arrested as bymeans of an inwardly turned iiange 4| formed on the upper end ofthe'support i6 the weight 38 may means of an adjusting screw 42.

The lower end of the pin as indicated at 43 to slidably receive anactuator 44 which is in turn formed with a foot 45 ybearing upon asubstantially laterally extending arm 46 ofa bell crank 41'. A smallcompression spring 48 is preferably interposed between thel foot 45 andthe lower end ofthe pin 31 so that when the weight=33 is moveddownwardly as a result of an upward jerk on the cable 6, a downwardforceisexerted on the arm 46 through the compression spring 48, thespring 48 serving as a cushion to prevent unduly abrupt application offorce to the bell crank 41.

The bell crank 4 1 is preferably urged to a position such as thatillustrated in Fig. 2 by means of a ltension spring 49 interconnectingthe arm 46 withthe laterally bell crank 41 is preferably drivablyconnected to the switch member 22, this lattermember comprising a bell4crank having a horizontally extend.- l

ing 'arm 50 which lis interconnected with the. arm 46 of the bell crank41 as by means of a link I. The bell crank 41 is supported for pivotalmovement as by means of a pivot pin 52 carried by a supporting bracket53 which is in turn secured to the supportl I6 and a similarconstruction is employed for mounting. the switch member 22 for pivotalmovement.

The switch member 22'carries on a downwardly 54 thereof an electricalcontact 55 which ispreferably insulated from the arm 54 and connectedlas by means oi an electrical conductor 56 to the negative terminalbattery 24. This connection may be Vaccomplished by means of aconstruction such as that illustrated in Fig. 4 wherein an insu- 35 andfrom slidably guides a pin-` 36. Theweight 36 andV and downward movementofv be limited and adjusted as by 31 is preferably boredextendingsupport 34. The' lating supporting ring 51 is illustrated as beingsecured as by means of screws 53 to the sides of the support, The ring51 supports a metal plate 5 6 carrying a Abinding post 60 to whichtheconductor 56 is attached. `'I'heundei side of the plate 59 supports acompression springiilv which may be secured thereto as by spot welding,soldering or other suitable means, the compression spring 6l beingadapted to engage the bottom or case of the dry batteries 24.

The ring 51 -and plate 59 are preferably dis- 'posed in such locationthat the center pole or positive terminal 62 of the lbattery 24 willrest upon the upper end or contact terminal 63 of the igniter 25 whenthe mechanismis assembled in the manner illustratedin Fig.v2.,

Since one electrode of the igniter 25 is grounded to the housingIllthrough Ithe connector I4, it will .be seen that anl electricalcircuit will be completed through the ignition member 2 1 whenever theelectrical contact member 55 is connected to ground orto a metallicmember which is in turn connected to the casing l0. Since the casing I0might be subjected to jerks and jars suicient to actuate the inertiadevice 2l during the lowering of the tool to the desired `location inthe well bore, it is considered necessary to provide some means forpreventing the completion of the aforementioned electrical circuit untilafter the elapse of a definite time interval. For this purpose I employa timing device 64 which may conveniently comprise an'inexpe'ns'ivespring driven time keeping mechanism, such as' aninexpensive watch or adevice suchA as is illustrated in Fig. 2 35 f of the Phipps Patent N o.2,156,228, the timing mechanism 64 being suitably secured'to'andsupported by the support-,16.

The shaft of the watch 64 which normally drives the minute hand of thewatch is connected to a contact plate 65 land may be constructed alongthe lines illustrated in- Fig. 3. The plate 65 consists of a circulardisk 66 of metal or other electrically conductive material, uponthejupper 45 surface of which is secured 'a 'relatively thick disk 61 ofinsulating .material. The disk 61 is preferably provided with a notch 66of a width substantially equal to thewidth of the cont/act member 55 sothat the contact member 55 cannot be engaged with t 'e plate 65 untilthe disk 66 has been rotated'to a position aligning the notch 68 withthe contact member 55. Thus, in-

advertent operations of the inertia-device 2i will serve only to bringthe contact member 55 into engagement Withthe insulated disk 61 and willthus fail to complete the electrical circuit which is necessary for theactuation of the igniter 25.

Upon assembling the device preparatory to lowering it into a well bore.-the disk65 is positioned so as to require. the; elapse of apredetermined time period before the firing circuit can be completed.The device with the tool attached is then lowered into the well bore tothe desired location and as soon as'the time'period has elapsed, thecable 1 is given a jerk, whereupon theinertia device serves to cause thevcontact member 55 to penetrate the notch 68 and complete the electricalcircuit, with the result that the explosive 26 is ignited and theexplosive operated tool 6 is thus operated.

It may be `desirable to provide a mechanical inter-lock for additionally,protecting the equipment againstinadvertent operation.` This may beaccomplished by providing a second timing 75 mechanism 69 identicalinconstruction with the timing mechanism 84 previously described andcarrying an inter-locking disk 18. identical in construction with thedisk .88 previously described. L

'I'he bell crank I1 is provided with a downwardly extending arm 1|adapted to arrest plvotal movement of the bell crank 81 before theswitch arm 22 is moved to circuit closing position by engagement of thearm 1| with the surface of the insulating material 81. `It will thus beseen that in order for a Jerk on the cable l to energize the igniter, itis necessary for the notches 88 in each of the disks 18 and 88 to be,respectively, aligned with and the contact member 55. This mechanism,therefore, serves to insure that the device will not be actuated byinadvertent Jerks or accelerations or decelerations of the cable duringthe time the tool is being lowered into the well bore.

Attention is furthermore directed to the fact vthat if, for any reason,the tool fails to ire at the intended time. the tool may be hoisted tothe ground surface in complete safety since once the notches 88 havemoved past their respective bell crank' arms, the tiring circuit cannotbe com'- pleted by subsequent actuation of the inertia device 2|. y

I have illustrated in Fig. 5 a preferred form of construction of acasing perforator which is particularly adapted for use with a firingdevice above described. The perforator 8 comprises a long` cylindricalpiece of metal which is recessed and threaded at its upper end toprovide a boss 1| a permitting threaded attachment of the perforator 8.to the pin end |5 of the iiring device 8.

From the lower center of the boss 1|a a powder or firing channel 12 isextended vertically for substantially the full length of the perforator,the channel 12 being packed with powder or other suitable explosivematerial 18 and the channel J2 being intersected at suitably frequentintervals by gun barrel receiving bores 1d. These bores are eachthreaded as indicated at 15 and counter-bored at their outer ends asindicated at 18 to permit the insertion into the bore 14 of a gun barrelunit 11, the unit 11 being threaded externally so as to engage thethreads 15 and being preferably also headed as indicated at 18 to permitthe clamping of a sealing ring or washer of gasket material 18 betweenthe head 18 and the bottom of the counterbore 18.

Each of the barrel units 11 is preferabl; bored i as indicated at 88 toreceive a'steel bullet or projectile 8|, the space behind the bullet 8|being lled or packed withpowder` or other suitable explosive material82. The wall thickness of each of the barrel umts 11 is made sufhcientto withstand the bursting forces developed by'the ignition of theexplosive 82. The, circumference of the unit 11 is preferably grooved asindicated at 83 in Fig. 6 'and a number of radially extending bores orports 84 communicate between the groove 88 and the central bore 88so asto carry the burning of the powder 18 intothe chamber behind the bullet8| and so re vthe explosive 82 carried thereby.

i The bore 88 is preferably internally recessed as indicated at 85 so asto permit a retaining ring 88 of relatively soft materialsuch as copperto be swaged into the recess. This -serves to prevent expulsion of theprojectile 8| upon the ring ofthe explosive '82 until a considerablepressure has been developed by the explosive, at which time the ring 88shears on the bellcrankarm'itand the projectilev is discharged withgreat force from the barrel- 88.

iired when the flame producing through which one side to the other Fluidleakage past the bullet 8| is preferably prevented by the insertion intothe bore 88 of a rubber or cork plug 81. Ready removal of the gunbarrelunit 11 from the body member 8 may be permitted by providing a recess 88adapted to receive a spanner permitting the unscrewing of the unit. 11so as to disengage its threaded connection with the body member 8.

In case the perforator is to be used with casing having an interiordiameter considerably larger than the exterior diameter of the unit 8which is illustrated in Fig. 5, I prefer to remove the relatively shortgun barrel umts 11 illustrated in Fig. 5 and Substitute thereforrelatively long gun barrel umts 11a of the character `illustrated inFig. '1 so as to provide a longer length of barrel the projectile 8| 81mperforator for each I have illustrated in 88 is positioned a tileassembly 88.

The assembly 88 comprises a cylindrical sleeve 8| adapted to be insertedinto the bore 88. Opposite ends of the sleeve 8|,are closed by pro-.iectiles 82 and 83 each of which is formed near its rearward end with ahorizontally extending groove 84 into which the end of the sleeve 8| isswaged or clampedas is illustrated at 85. This serves to secure theprojectiles 82 and 83 to the sleeve 8| and at the same time close theends thereof so The central portion of the sleeve 8| is deformed orexterior/ly machined to provide an externally circumferentiallyextending groove 81 disposed'in such location longitudinally of thesleeve 8| as to be positioned adjacent the firing channel 12a when thecartridge 88 is inserted within the bore 88 in the manner illustrated inFig. 8. The groove 91 thus serves to provide a communication between-thefiring channel 12a and the con.- tinuation 12b thereof. vThe sleeve 8|is provided with one or more perforations 88 positioned in the bottom ofthe recess 81 and providing a communication between the recess and theinterior oi' the cartridge so that the charge 88 of gun powder containedwithin the cartridge may be material 18a with which the channel 12a isillled is ignited as previously described.

When .the charge 88 is red, the projectiles 82 and 88 are forciblyejected-in opposite directions from the bore 88 so as to simultaneouslyperforate the casing on opposite sides of the perforator body.

From the foregoing havey shown and described a novel gun perforator itwill be observed that I the ilring mechanism above described is soarranged as to require .the elapse of a predetermined time period beforethe same can be actuated and such that if the explosive in the tool isnot fired during such predetermined time period, the same can be safelywithdrawn from the well bore without danger of an inadvertent explosion.v

It will also be observed that the ring mechanism above describedprovides for the actuation of an explosive operated oil well toolwithout requiring the use of either electrical conductors extending fromthe ground surface or the use of go-devils adapted to be slid down thecable used to support such tools.

While I have shown and described the preferred embodiment -of myinvention, I do not desire to be limited to any of the details of con..struction shown or described herein, except as defined in the appendedclaims.

Iclaim: y

l. In a firing device, a housing having means on one end for attachmentto a cable for lowering said housing through a well bore to a desiredlocation therein and having means on the other end for attachment to anexplosive operated oil well tool, said housing containing the followinginstrumentalities:

cause operation of said tool; inertia' means operable to operatesaid'igniter in response to accelerating movement of said housing'freelyin said well bore; and timing means for preventing actuation of saidigniter until the elapse of a predetermined time period of sulcientlength to permit lowering of said housing to said desired locationduring said period.

2. In a nring device, a housing having means on one end for attachmentto a cable for lowering said housing through a well bore to a desiredlocation therein and having means on the erated oil well tool, saidhousing ,containing the following instrumentalitles: anigniteractuatable` to cause operation of said tool; a weight mounted anigniter actuatable to other end for attachment to an explosive opforvertical movement relative to said housing;

a spring interposed between said weight and said housing for normallylsupporting said weight A while permitting vertical movement thereofrelative to said housing in response to accelerating movement of saidhousing freely in said well bore;

control means connected to said weight and opl erable in response tomovement thereof relative to said housing to actuate said igniter; andtiming means for preventing operation of said c ontrol nieans-until theelapse of a'predetermined time period of sunlcient length to permitlowering of said housing to said desired -location during said period.

3. In a nring device, a housing having means on one end for attachmentto a cable for lowering said housing into a well bore and having meanson the other end for attachment to an explosive operated oil Awell tool,said housing containing the following instrumentalities: an igniteractuatable to cause operation of said tool; a weight mounted forvertical movement relativeto said housing; a spring interposed betweenweight and said housing for supporting said weight; control meansconnected to said weight and operable in response to movement, thereofto actuate said igniter; timing means for preventing operation of saidcontrol means until the elapse of a predetermined times; and anothertiming n means for preventing actuation of said igniter switch meansin'said circuit closable to energize said igniter in response to anabrupt movement of said housing.

5'. In a firing device, a housing having means on one end for attachmentto a cable for lowering said housing into a well bore and having meanson the other end for attachment to an explosive operated oil well tool,said housing containing the following instrumentallties: an igniterenergizable to cause operation of said tool; a battery for energizingsaid igniter connected in circuit therewith: normally open switch meansin said circuit including a. member movable to a position completingsaid circuit and energizing said igniter; inertia means movable relativeto said housing in response to an abrupt movement of said housing; andmeans interconnecting said switch means and said inertia means formoving said member to circuit closing position in response to movementof said inertia means.

6. In a ring device, a housing having means s said housing in responseto an abrupt movement I of said housing; means interconnecting' saidswitch means and-said inertia means for moving said memberto circuitclosing position in response to movement of said inertia means; a

movable stop normally disposed in a position to arrest movement of saidinertia means before said member is moved to circuit closing'position;and timing means for moving said stop to a position permitting freemovement of said inertia means upon the elapse of a predetermined time.7. In a iiring device, a housing having means on one end for attachmentto a cable for lowering said housing into a wellbore and having means onthe other end for attachment to anw explosive operated oil well tool,said housing containing the following linstruir'ientalities: an igniterenergizable to cause operation of said tool;

-a battery for energizing said igniter connected in circuit therewith;normally open switch means in said circuit including a member movable toa position completing said circuit and energizing saidigniter; inertiameans movablerelative to said'housing in response to an abrupt movementof said housing; means interconnecting said switch means and saidinertia means for moving said member to circuit closing position inresponse to movement of said inertia means; a

period.

movable stop normally disposed in the path of movement of said memberfor engaging and arresting said member before it is moved to circuitclosing position; and timing means for moving lsaid stop out of the pathof movement of said member upon the elapse of a predetermined time. 8.In a firing device, a housing having means on one end for attachment toa cable for lowering said housing into a well bore and having meansv onthe other end for attachment to an explosive operated oil well tool..said housing containing the following instrumentalities: an igniterenergizable to cause operation of said tool: a battery for energizingsaid igniter connected in cirspouse to movement of said inertia means; ay

movable stop normally disposed in a position to arrest movement of saidinertia means before said member is moved to circuit closing position;timing means for moving said stop to a position permitting free movementof said inertia means upon the elapse of a predetermined time: a secondmovable stop normally disposed in the path of movement of said memberfor engaging and arresting said member before it is moved to circuitclosing position; and a second timing means for'moving said second stopout ofthe path of movement of said member upon the elapse of saidpredetermined time.

9. In a/iiring device, c, housing having means on one end vforattachment to a cable for lowering said housing into a well bore andhaving means on the other end for attachment to an explosive operatedoil well'tool, said housing containing the followinginstnimentalities:an igniter actuatable to cause operation of said tool;` inertia meansoperable to actuate said igniter in response to an abrupt movement oisaid housing; and timing means for permitting actuation oi' said igniteronly during a predetermined time 10. In a firing device,`a housinghaving means on one end for attachment to a cable for lowering saidhousing into a well bore and having means on the other end forattachment to an explosive operated oil well tool, said housingcontaining the following instrumentalities: an igniter energizable tocause operation of said tool; a battery for energizing said igniterconnected in circuit therewith; normally open switch means in saidcircuit including a member movable to a position completing said circuitand energizing said igniter; inertia means movable relative to saidhousing in response to an abrupt, movement of said housing; meansinterconnecting said switch means and said inertia means for movingsaid'member to circuit closing position in response to movement oi.'said inertia means: a movable stop normally disposed in a position toarrest movement of said inertia means before said member is moved tocircuit closing position; and timing means for moving said stop to aposition permitting free movement of said inertia means upon the elapseof apredetermined time and `for moving said stop to said normal positionupon the lelapseof another predetermined time.

11. In a gun perforator, the combination of:

an elongated body lmember adapted to be lowered into a well bore andhaving a longitudinally extending firing channel for receiving amaterial capable oi' burning with great rapidity; a plurality -of gunbarrel umts carried by said body member, each defining a transverselyextending projectile guiding bore, each oi said units including achamber for receiving an explosive and a plurality of ports extendingtransversely of and intersecting said projectile guiding bore andcommunicating with said channel; and means detachably securing each oisaid units in said body member, whereby said units may be re-.

moved and other units of diii'erent length substituted therefor to adaptthe perforator for the perforation of a diiierent size of oil wellcasing.

12. A gun'barrel unit for use with a gun perforator including a bodymember adapted to be lowered into a well bore and having alongitudinally extending ring chamber for receiving a material capableof burning with great rapidity and having a plurality of laterallyextending gun barrel receiving recesses intersecting said channel, saidunit comprising: a thick walled barrel member insertable in said recessand defining a projectile guiding bore, said bore being intersected by aplurality of transversely extending ports disposed .in a position toalso intersect said channel when said member is inserted in said recess.

13. A gun barrel unit for use with a gun periorator including a bodymember adapted to be lowered into a well bore and having alongitudinally extending firing chamber for receiving a material capableof burning with great rapidity and having a plurality of laterallyextending gun barrel receiving recesses intersecting said channel.saidunit comprising: a thick walled barrel member insertable in saidrecess and defining a projectile guiding bore, said bore beingintersected by a plurality of transversely extending ports disposed in aposition to also-intersect said channel when said member is inserted insaid recess. said barrel member having a circumierentially extendinggroove formed in its exterior surface communicating with all of saidports to provide communication between said ports and said channel 'whensaid barrel member is inserted in said recess with said ports disposedout of alignment with said channel.

14. In a gun perforator, the combination of: an elongated body memberadapted to be lowered into a well bore and having a projectile guidingbore extended transversely through said body member from one side to theother thereof in a position to intersect a firing channel formed in saidbody: a projectile in each of the outer ends of said bore'; and acartridge extended between and secured to said projectiles, saidcartridge being illled with an explosive material and having a portcommunicating between said tiring channel and the interior of saidcartridge.

v15. For use with a, gun perforator having a projectile guiding boreextended transversely through the body thereof and intersecting a firingchannel formed therein, a cartridge construction comprising acylindrical sleeve insertable in said bore for holding a supply ofexplosive material, said sleeve having a circumferentially extendinggroove formed in the outer surof said sleeve; and a projectile tted intoeach end of said sleeve, each of said projectiles having acircumferentially extending groove formed therein and the correspondingend of said sleeve being clamped into said groove to secure saidprojectile to said sleeve.

16. In a firing device, a -housing having means on one end forattachment to a cable for lowering said housing into a well bore andhaving means on the other end for attachment to an explosive operatedoil well tool, said housing containing the following instrumentalities:an igniter actuatable to cause operation of said tool; control meansoperable to actuate said igniter; timing means for preventing operationof said control means until the elapse of a predetermined time; andanother timing means for preventing actuation of said igniter until theelapse of said predetermined time.

17. I n a ring device, a housing having means on one end for attachmentto a cable for lowering said housing intoa well bore and having means onthe other en d for attachment to an explosive operated oil well tool,said housing containing the following instrumentalities: an igniterenergizable to cause operation of said tool; a battery for energizingsaid igniter connected in circuit therewith; normally open switch meansin said circuit including a member movable to a position completing saidcircuit and energizing i position permitting free movement of saidconsaid igniter; control means movable relative to said housing; meansinterconnecting said switch means and said control means for moving saidmember to circuit closing position in response to movement of saidcontrol means; a movable stop normally disposed in a position to arrestmovement of said control means before said member is moved to circuitclosing position; and timing means for moving said stop to a positionpermitting free movement of said control means upon the elapse of apredetermined time.

18. In a firing device, a housing havingmeans on one end for attachmentto a cable for low- Y ering said housing into a well 4bore and havingmeans` on the other end for attachment to trol means upon the elapse ofa predetermined time; a second movable stop normally disposed in thepath of movement of said member for engaging and arresting said memberbefore it is moved to circuit closing position; and a second timingmeans for moving said second stop out of the path of movement of saidmember upon the elapse of said predetermined time.

19. In a iiring device, a housing having means on one end for attachmentto a cable for lowering said housing into a well bore and having meanson the other end for attachment to an explosive operated oil well tool,said housing containing the following instrumentalities: an igniteractuatable to cause operation of said tool; control means operable toactuate said igniter in response to an abrupt movement of said housing;and timing means for permitting actuation of said igniter only duringapredetermined time period.

20. In a firing device, a housing having means on one end for attachmentto a cable for lowering said housing into a well bore and having vmeanson the other end for attachment to an an explosive operated oil welltool, said housing Y containing the following instrumentallties: anigniter energizable to cause operation of said tool; a battery forenergizing'said igniter connected in circuit therewith; normally openswitch means in said circuit including a member movable to a positioncompleting said circuit and energizing said igniter; control meansmovable relative to said housing: means interconnecting explosiveoperated oil well tool, said housing containing the followinginstrumentalites: an igniter energizable to cause operation of saidtool; a

battery for energizing said igniter connected in circuit therewith;normally open switch means in said circuit including a member movable toa position completing said circuit and energizing said igniter; controlmeans movable relative to said housing; means interconnecting saidswitch means and said control means for moving said member to circuitclosing position in response to movement of said control means; amovable stop normally disposed in a position to arrest movement of saidcontrol means before said` member is moved to circuit closing position;and timing means for moving said stop to a position permitting freemovement of said control means upon the elapse of a predetermined timeand for moving said stop to said normal position upon the elapse ofanother predetermined time.

JACK JOHNSON.

